WdmlibRtlInitUnicodeStringEx function (wdmsec.h)

The WdmlibRtlInitUnicodeStringEx function initializes a counted string of Unicode characters.


NTSTATUS WdmlibRtlInitUnicodeStringEx(
  [out]          PUNICODE_STRING DestinationString,
  [in, optional] PCWSTR          SourceString


[out] DestinationString

A pointer to the UNICODE_STRING structure to be initialized.

[in, optional] SourceString

A pointer to a null-terminated wide-character string. This string is used to initialize the counted string pointed to by DestinationString.

Return value

WdmlibRtlInitUnicodeStringEx returns STATUS_SUCCESS if successful, otherwise the method may return other NTSTATUS values.


The routine copies the SourceString pointer value to the Buffer member of the UNICODE_STRING structure pointed to by DestinationString. The Length member of this structure is set to the length, in bytes, of the source string, excluding the terminating null. The MaximumLength member of the structure is set to the length, in bytes, of the source string, including the terminating null. If SourceString is NULL, Length and MaximumLength are both set to zero.

WdmlibRtlInitUnicodeStringEx does not alter the source string pointed to by SourceString.


If the source string is longer than MAX_USTRING - 1 bytes, WdmlibRtlInitUnicodeStringEx sets the Length member of the UNICODE_STRING structure pointed to by DestinationString to MAX_USTRING - 2, and sets the MaximumLength member of this structure to MAX_USTRING. In this case, the Length and MaximumLength values misrepresent the length of the null-terminated source string, and relying on the accuracy of these values is potentially dangerous.

Callers of WdmlibRtlInitUnicodeStringEx can be running at IRQL <= DISPATCH_LEVEL if the DestinationString buffer is nonpageable. Usually, callers run at IRQL = PASSIVE_LEVEL because most other RtlXxxString routines cannot be called at IRQL > PASSIVE_LEVEL.


Requirement Value
Minimum supported client Available starting with Windows 2000.
Target Platform Universal
Header wdmsec.h (include Wdmsec.h, Wdm.h, Ntddk.h, Ntifs.h)
Library NtosKrnl.lib
DLL NtosKrnl.exe
IRQL See Remarks section.

See also